                              :y2 ry
                              :markerEnd "url(#arrow-point)"})))
           (svg-element (assoc layer
+                              :key (str (:db/id layer) "-handler")
                               :className (str "arrow-handle "
                                               (when (om/get-state owner :hovered?)
                                                 "hovered "))

    (render [_]
      (let [cast! (om/get-shared owner :cast!)
            [rx ry] (om/get-state owner :mouse-pos)
            camera (cursors/observe-camera owner)
            center (layers/center layer)]
        (dom/g #js {:className "arrow-handle-group"}
          (when (and rx ry)

                                                  {:dest layer
                                                   :x (first (cameras/screen-event-coords e))
                                                   :y (second (cameras/screen-event-coords e))}))))
          (svg-element (assoc layer :className "arrow-outline"
                              :key (str (:db/id layer) "-outline"))))))))

(defn arrows [app owner]
  (reify
